1. Technical Field
The present invention relates to a printing system that has plural devices for printing on printing paper, and to a control method for the printing system.
2. Related Art
Japanese Unexamined Patent Appl. Pub. JP-A-2007-175948 teaches a photograph printer that has a reverse printing device that prints on the back side of the recording paper (the uncoated non-printing side), and an image recording unit that prints a photograph on the front side of the recording paper (the coated printing side). In the photograph printer taught in JP-A-2007-175948, the reverse printing device is a dot impact printer, and the image recording unit is an inkjet printer. The recording paper is supplied in this photograph printer from a loading unit in which recording paper that is wound into a roll is loaded, and the recording paper supplied from the loading unit is cut by a cutter. Text and photograph printing are performed after the recording paper is cut, and after printing is completed, the printed sheets are sorted by a sorter.
Printers that print on recording paper using a printhead are also known from the literature. Japanese Unexamined Patent Appl. Pub. JP-A-H09-314959, for example, teaches a printer that has a main control unit that controls printer operation, a head control unit that controls driving the printhead, and a carriage control unit that controls printhead movement. In the printer described in JP-A-H09-314959, the CPU of the main control unit, the CPU of the head control unit, and the CPU of the carriage control unit are communicably connected to each other. If any one of the three CPUs in this printer detects a printer problem, it reports the problem to the other CPUs, and the three CPUs each independently execute an appropriate error-handling process.
If a problem occurs in any one of the component devices of the photograph printer taught in JP-A-2007-175948, that is, the reverse printing device, the image recording unit, the loading unit, the cutter, or the sorter, and operation of the devices in which a problem has not occurred is not stopped, the devices in which a problem has not occurred could be damaged. For example, if a problem occurs in the loading unit and the reverse printing device continues operating even though the recording paper is not supplied, the platen disposed opposite the printhead of the reverse printing device could be damaged. As a result, when a problem occurs in one device, operation of the other devices in which a problem has not occurred is preferably stopped as quickly as possible.
If the plural devices are connected to a common power supply, the other devices in which a problem has not occurred can be stopped immediately by cutting off the common power supply. However, if the common power supply to which the plural devices are connected is cut off to immediately stop the other devices in which a problem has not occurred, there could be a device that cannot be stopped appropriately. As a result, if the common power supply is turned off to abruptly stop plural devices, one of the other devices in which a problem has not occurred could be damaged.